We should refactor the agent cli output

[huchen2021]

Fixes #253

There are a lot of wrong flag for byoh-hostagent

1. The following flags belong to "cli", not " byoh-hostagent". It should put all flag function in main function of "cli", not as global variable.

• -bundle-repo string
• -cache-path string
• -detect
• -install
• -k8s string
• -list-supported
• -os string
• -preview-os-changes
• -tag string
• -uninstall

2. The following flags belong to klog which we don't need it anymore

• -add_dir_header
• -alsologtostderr
• -log_backtrace_at value
• -log_dir string
• -log_file string
• -log_file_max_size uint
• -logtostderr
• -skip_headers
• -skip_log_headers
• -stderrthreshold value
• -v value
• -vmodule value

After fix this, byoh-hostagent only has the following flags:

• -downloadpath string
• -kubeconfig string
• -label value
• -metricsbindaddress string
• -namespace string
• -skip-installation

Plus, In order to avoid such a bug again, I add a test for --help command. Any unexpected option will caused the test failure.

[anusha94]

Can we write a test for -h or --help command?

[huchen2021]

Can we write a test for -h or --help command?

Yes, it will help us to avoid such a bug again. Done. Please review it again.

[anusha94]

lgtm

[dharmjit]

LGTM.

Could we keep all flag-related tests in a single test file.?

[huchen2021]

LGTM.

Could we keep all flag-related tests in a single test file.?

We already have label_flag_test.go. And If we put label_flag_test.go and help_flag_test.go together, it would be huge file. And if we have any other flag test in the future, and all put in one file, it will became a super huge file. Don't think it is a good idea.

[dharmjit]

We already have label_flag_test.go. And If we put label_flag_test.go and help_flag_test.go together

Again no strong opinions, but IMO we are keeping a single test file for a package, here for agent main we split that into 2 files agent_test.go and label_flag_test.go as the functionalities are different and it does not require envtest/k8s client, etc.